Question

π/4=1-1/3+1/5-1/7+1/9...+1/(4n-3)-1/(4n-1)C语言程序怎么编

Answer 1

double GetPi(int n)
{
double Pi=0.0;
for(int i=1;i<=4*n-1;i+=2)
{
if((i/2)%2==0) Pi+=1.0/i;
else Pi-=1.0/i;
}
return 4*Pi;
}

Answer 2

#include<iostream>
#include<cmath>
using namespace std;
int main()
{

double p=0,j=1;
int i;
for( i=1;fabs(j)>1e-7;i+=2)
{
j=pow(-1,(i-1)/2)/i;
p+=j;
}
printf("%10.8f\n",4*p);

return 0;
}

Answer 3

#include<stdio.h>
#include<math.h>
void main()
{
double p=0,j=1;
int i;
for( i=1;fabs(j)>0.00001;i+=2)
{
j=pow(-1,(i-1)/2)/i;
p+=j;
}
printf("%lf\n",p);
}

Answer 4

#include<stdio.h>
int main()
{
int i,n;
double pi=0,x=0;
scanf("%d",&n);
for(i=1;i<=n;i++)
{
x=(double)(8)/((4*i-3)*(4*i-1));
pi=pi+x;
}
printf("%lf",pi);
return 0;
}